We have found that lymphocytes isolated from human intestinal mucosa contain T cells, B cells, macrophage and Fc receptor bearing lymphocytes and can mediate antibody dependent cellular cytotoxicity for chicken RBC targets and lectin induced cellular cytotoxicity for human RBC targets. No differences was seen between normal and inflammatory bowel disease intestines. Proposed studies will examine the ability of normal and IBD human intestinal lymphocytes to be stimulated in mixed lymphocyte culture and to mediate cell mediated lympholysis. Also antibody (IgA, IgG, and IgM) synthesis and secretion will be examined. Finally, cell separation techniques will be used to determine the nature of the lymphocyte subpopulations which mediate cellular cytotoxicity.